Empyrion I - The Search for Fierra (1985)
Orion Treet's job is to observe and chronicle the growth of a new extraterrestrial colony: Empyrion. Arriving on the planet Fierra, Treet discovers a civilization in decline; to survive, he must unscramble its mysteries before time runs out for the settlement.
Empyrion II - The Siege of Dome (1986)
Treet determines to return to Dome after his brief respite among the peaceable, graceful Fieri. Abandoned by his companions from Earth, Treet becomes a solitary figure in a deadly civil war.